This invention relates to a method of operating an oscilloscope.
Until recently, most digital storage oscilloscopes had a rather low acquisition rate, such that a conventional digital storage oscilloscope might not display an infrequent event.
The digital oscilloscope described in U.S. Pat. No. 5,986,637, the entire disclosure of which is hereby incorporated by reference herein for all purposes, has a very high acquisition rate which allows the user to view infrequent anomalies that might previously have been overlooked due to the low acquisition rate of a hitherto-conventional digital storage oscilloscope. After noticing an anomaly in the signal, the user might want to learn more about a potential problem that might be indicated by the signal and the user will accordingly want to adjust the acquisition parameters of the oscilloscope to trigger on the anomaly.
Current digital storage oscilloscopes have the ability to trigger on a variety of signal features. For example, one advanced trigger capability is known as runt triggering. Runt triggering is typically invoked when the oscilloscope is being used to display the waveform of a digital signal, in which rising and falling edges pass through upper and lower threshold levels. In the context of a digital signal, the term “runt pulse” is used to refer to a pulse whose amplitude is significantly less than that of the normal pulses of the digital signal, such that the leading edge of a runt pulse passes through only one of the threshold levels before the signal level returns, on the trailing edge, to the level that it had immediately prior to the leading edge.
In order to invoke runt triggering in a conventional digital storage oscilloscope, the user must select runt triggering from a trigger mode menu, measure the peak-to-peak amplitude of the runt pulse, and supply the measured amplitude value to the oscilloscope. When runt triggering is properly invoked, the oscilloscope will be triggered only if it receives a pulse of peak-to-peak amplitude less than the specified value. The user may also measure the pulse width of the runt pulse and supply this value for use in further qualifying the acquisition parameters.
Advanced trigger capabilities, such as the runt trigger capability, provide the oscilloscope with valuable qualities as a test and measurement instrument but an occasional user of the oscilloscope might not be aware of many of the advanced trigger capabilities or, if aware, might not be familiar with the procedure for setting up the oscilloscope to take maximimum advantage of the trigger capabilities.